The present invention relates to a particle beam irradiation system suitable for a particle-beam treatment making use of a charged particle beam (an ion beam) of a proton, a heavy ion, and so forth, and in particular, to a particle beam irradiation system capable of promptly realizing control of a change in beam-energy, and easily realizing reproducibility of the performance of an irradiation beam, and a method for operating the same.
A particle beam treatment whereby an affected part of a patient with a cancer is irradiated with an ion beam of a proton, or a heavy ion, and so forth, for treatment, has been well known as radiotherapy for a cancer. An ion beam irradiation method includes a scanning irradiation method as disclosed in “REVIEW OF SCIENTIC INSTRUMENTS”, Vol. 64, No. 8, (August 1993), pp. 2074-2093.
In the case where a synchrotron is adopted as an ion beam generator for controlling a change in beam-energy, required in the scanning irradiation method, there is available a multistage extraction-control operation for realizing irradiation with plural ion beams differing in energy from each other, in one operation cycle inside the synchrotron, disclosed in Japanese Patent No. 4873563, Japanese Unexamined Patent Application Publication No. 2011-124149, and “Nuclear Instruments and Methods in Physics Research”, No. A624, (September 2010), pp. 33-38, respectively, as a control method for realizing the control of a change in beam-energy.